Elucidation of mechanism of nonuniform plastic deformation by using oligocrystalline metal sheets

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K14856
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18020:Manufacturing and production engineering-related
• Research Institution: Tohoku University
• Principal Investigator: Ueshima Nobufumi 東北大学, 工学研究科, 助教 (10733131)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 有限要素多結晶モデル / 塑性変形

Outline of Final Research Achievements

The number of the grains in copper wires or connectors has been decreasing due to the miniaturization of the products. In this study, the measurements of strain distribution during tensile testing of oligo-crystalline specimen and calculations using finite element polycrystal model have been carried out. The measured and calculated stress-strain curve and strain distributions were compared. The measured deformation behavior well-agreed with the prediction by the theories of plastic deformations. The comparison of experiment with calculation clarified that the calculation can reproduce the strain distribution of the specimen of which the number of grains is a few. On the other hand, the calculation cannot reproduce the strain distribution of the specimen of which the number of grains is relatively many. These results show the limitation of the model and hardening rules and the guideline to improve the calculation model for oligo-crystalline materials was obtained.

Free Research Field

金属材料学

Academic Significance and Societal Importance of the Research Achievements

学術的には流動応力や集合組織などのマクロな変形挙動を予測できるモデルであっても、結晶粒毎のひずみ分布などミクロな変形挙動を予測できない場合があることを示し、モデルの改善につながる成果が得られたと考えられる。社会的には、材料に含まれる結晶の数が少ない場合の変形予測について、予測可能な場合と困難な場合を示し、予測の可否について実例を示し、そのような材料の加工の予測の際の指針を示した。